When President Trump last week started a six-month countdown clock to end his predecessor's executive order protecting immigrants who were brought illegally to America when they were children, the denunciations came fast, furious, and fevered. Angry outrage has become the standard reaction to almost everything Trump says and does, often with reason. But on the issue of Deferred Action for Childhood Arrivals, or DACA, that fury is misplaced. Trump has created an opening that should gladden conservatives and liberals alike — one that members of Congress on both sides of the aisle should exploit.

For years, legislators have allowed presidents to push the limits of executive power, bypassing Congress on issues ranging from warrantless wiretaps to health care subsidies. Lawmakers, constantly battling each other, have failed to defend what should be their exclusive power to make the nation's laws. Unexpectedly, Trump has just handed them a chance to reclaim lost ground.

Barack Obama's DACA policy was a classic example of achieving an excellent end through terrible means. It offered to protect 1 million or so young people from deportation and allow them to work legally, so long as they stayed out of trouble, finished school, and registered with the government. More than three-fourths of eligible immigrants signed up for DACA status, and by all accounts they have been a productive and law-abiding cohort. Some have been downright heroic.

The problem with DACA is that it was imposed unilaterally by Obama in 2012. He claimed he had to take "action to change the law" by executive order because Congress had failed to pass a bill (the proposed DREAM Act) that would do so legislatively. At first he insisted that DACA was only a "temporary stopgap measure." But as hundreds of thousands of so-called "Dreamers" signed up, DACA became institutionalized. Two years later, Obama tried to expand it, sheltering not only Dreamers from deportation, but their parents — a population numbering more than 4 million. When a group of states sued to block the expansion, federal courts backed them up. Obama's action was "manifestly contrary" to existing immigration law, ruled the Fifth Circuit Court of Appeals, and presidents cannot make immigration law by fiat.

But DACA itself remained in force, and there is no question that the policy is popular. An overwhelming 76 percent of voters, say DACA enrollees should be allowed to stay legally in the United States; only 15 percent want them deported. Majorities of Democrats (84 percent), independents (74 percent), and Republicans (69 percent) believe Dreamers should able to remain in America as permanent legal residents. Even among self-identified Trump voters, two-thirds think Dreamers should stay.

Even granting Trump's habit of saying "X" on Monday and "not-X" on Thursday, it seems plain that a clean bill giving Dreamers legal status is one he would relish signing — if only to tout it as an achievement only he could have engineered. "Congress now has 6 months to legalize DACA (something the Obama Administration was unable to do)," Trump tweeted on Tuesday. "If they can't, I will revisit this issue!"

No one should miss the significance of Trump's surprising deference to Congress. Trump used to say he would end DACA the way Obama created it: unilaterally. In his campaign kickoff speech in the Trump Tower lobby two years ago, he vowed that if elected he would "immediately terminate President Obama's illegal executive order on immigration."

But he didn't. He hesitated for months on DACA — and when he finally moved it was because of a looming legal threat: A group of state attorneys general were about to challenge DACA in court. If Trump wanted DACA killed without having to pull the trigger himself, he could have invited that lawsuit and ordered the Justice Department not to oppose it.

Instead he is urging Congress to take the lead and "legalize DACA." To put it differently, Trump is urging the legislative branch to reclaim its proper constitutional authority — to take back a measure of power that Obama usurped.

In modern times, presidents of both parties have routinely overstepped their bounds. Obama arguably went further down that paththan any previous president. "Once a presidential candidate with deep misgivings about executive power," The New York Times observed last year, "Obama will leave the White House as one of the most prolific authors of major regulations in presidential history." It took a while for Obama to get over those "misgivings" — after all, he had sharply criticized George W. Bush's reliance on unilateral orders. But once he did, he pursued executive power without apology.

Improbably, Trump has now handed Congress a perfect vehicle to undo an act of presidential overreach and enhance its own authority. For Republicans, this is an opportunity to roll back one of Obama's most blatant acts of "pen-and-phone" aggrandizement. For Democrats, it is a way to deter Trump from engaging in overreach of his own — from, say, ordering a wall to be built along the Mexican border on the grounds that Congress hasn't acted. For both, it is a chance to pass a bill that Americans by a wide margin would welcome.

Trump should be cheered, not cursed, for handing off DACA to Congress. For years, lawmakers of both parties have fumed as presidents have gotten away with wielding power unilaterally. Now Capitol Hill has a chance to do something about it, and with White House encouragement. Blow this opportunity, and they may never get another.